I am looking for advice on which injection point I should choose for my new Stenner pump.
1) Between heater and actuator valve Advantage - nice open area out of the way, thick coupling to tap into, able to sanitize spa if spa jets are running. Disadvantage - not after check valve, potential for bleach to enter heater, however, the Stenner should only run while pump is on.
2) Lower port on Rainbow 320 tab feeder Advantage - don't have to drill into plumbing. Disadvantage - danger of mixing tabs and liquid chlorine. What really are the risks here? I will likely never use tabs again and can label it very well to prevent others from doing it. I am more concerned about how well it needs to be cleaned out if it had tabs in it previously. Some posts say there is an explosion risk if it was EVER used for tabs in the past.
3) Top of t-fitting - I am afraid most of the injection will flow directly into the spa return and over-chlorinate the spa.
4) Bottom of t-fitting - I assume this is likely the best choice.